Peggy Renner-Howell lays flowers at a makeshift memorial near the Sikh Temple of Wisconsin on Aug. 7, 2012, in Oak Creek, Wis., where a gunman killed six people. / M. Spencer Green, AP

by Meghan Hoyer, USA TODAY

by Meghan Hoyer, USA TODAY

In the year since the movie theater massacre in Aurora, Colo., 23 mass killings in 19 states have taken the lives of 126 people. Six of the attacks were public killings in which many of the victims were unknown to their killers.

A USA TODAY database of these shootings over the past seven years shows that what Americans experienced over the past calendar year is sadly typical. There have been 14 such incidents since Jan. 1 of this year, while 2012 actually had a low for the reporting period: 22 mass killings. The high was 37 in 2006, the first year of the examination. (The FBI defines mass killings as murders that occur in a short time span and in which four or more people are killed.)

The massacre in Newtown, Conn., in December - during which Adam Lanza gunned down 20 children and six adults at an elementary school - became the moment of focus of myriad tragedies over the past year. The five other shootings that caught the nation's attention:

â?¢ In August, white supremacist Wade Michael Page fatally shot six people at a Sikh Temple in Wisconsin in what police called a hate crime. Page, 40, killed himself after an officer responding to the scene shot him in the stomach.

â?¢ After learning he'd been fired from his job, Andrew Engeldinger, 36, shot and killed five people at a Minneapolis sign company in September. He then killed himself.

â?¢ Two men were fatally shot in Mohawk, N.Y., and two more were shot at a car wash in Herkimer, N.Y., in March. Kurt Myers, 64, held police in a standoff overnight before they swarmed the building and killed him.

â?¢ In April, three people died when two bombs exploded near the finish line of the Boston Marathon. A police officer was killed a few days later after authorities publicized photos of two brothers considered suspects. One died in a standoff with police; the second, Dzhokhar Tsarnaev, 19, is charged with using a weapon of mass destruction.

â?¢ John Zawahri, 23, was shot dead by police in the library of Santa Monica College in June. Zawahri had killed his brother and father at home, carjacked a woman and shot at passersby before entering campus carrying an assault rifle.

The USA TODAY analysis of all such incidents since 2006 has found that they occur roughly every two weeks and that random public shootings such as Aurora and Newtown are anomalies. Typically, victims know their killers, and most are killed at home.

The other 17 mass killings in the past year - most either family slayings or murders that occurred in the course of a robbery or drug transaction - occurred off the national radar. On an American Indian reservation in North Dakota in November, a man entered his neighbor's house a block away and shot dead a grandmother and three of her grandchildren, then drove 20 miles to his father's home and killed himself. A man in Schenectady, N.Y., could face the death penalty in an arson that trapped a father and his three young children on the upper floor of their home in early May.

As is often the case in the wake of these high-profile events, the nation has undergone a sort of soul-searching involving the issues of gun control, mental health treatment and the undercurrent of violence in American society.

Though the high-profile cases, particularly Newtown, stirred outrage and spawned talk of new gun policies, the legislative impact has been minimal. Indeed, the U.S. Senate voted down measures in April that would have expanded background checks on gun buyers, along with other proposals, including an assault weapons ban.

Some states, including Nevada, California and New York, have either passed or are considering gun legislation ranging from expanding background checks to banning high-capacity magazines, which is what Lanza used in Newtown.